The wireless communications network has grown exponentially over the years. A Long-Term Evolution (LTE) system offers high peak data rates, low latency, improved system capacity, and low operating cost resulting from simplified network architecture. LTE systems, also known as the 4G system, also provide seamless integration to older wireless network, such as GSM, CDMA and Universal Mobile Telecommunication System (UMTS). In LTE systems, an evolved universal terrestrial radio access network (E-UTRAN) includes a plurality of evolved Node-Bs (eNodeBs or eNBs) communicating with a plurality of mobile stations, referred to as user equipments (UEs). The 3rd generation partner project (3GPP) network normally includes a hybrid of 2G/3G/4G systems. The Next Generation Mobile Network (NGMN) board, has decided to focus the future NGMN activities on defining the end-to-end requirements for 5G new radio (NR) systems.
Orthogonal Frequency Division Multiple Access (OFDMA) has been selected for LTE/NR downlink (DL) radio access scheme due to its robustness to multipath fading, higher spectral efficiency, and bandwidth scalability. Multiple access in the downlink is achieved by assigning different sub-bands (i.e., groups of subcarriers, denoted as resource blocks (RBs)) of the system bandwidth to individual users based on their existing channel condition. In LTE/NR networks, Physical Downlink Control Channel (PDCCH) is used for downlink scheduling. Physical Downlink Shared Channel (PDSCH) is used for downlink data. Similarly, in the uplink, Physical Uplink Control Channel (PUCCH) is used for carrying uplink control information (UCI). Physical Uplink Shared Channel (PUSCH) is used for uplink data.
In 3GPP LTE/NR systems based on OFDMA, the radio resource is partitioned into subframes or slots in time domain, each subframe/slot consists of a number of OFDM symbols. Each OFDMA symbol further consists of a number of OFDMA subcarriers in frequency domain depending on the system bandwidth. The basic unit of the resource grid is called Resource Element (RE), which spans an OFDMA subcarrier over one OFDMA symbol. A plurality of REs is grouped into physical resource blocks (PRBs), where each PRB consists of twelve consecutive subcarriers in one slot. In principle, coded UCI bits are assigned to an integer number of modulated REs for PUCCH transmission. However, the UCI codeword size may not be a multiple of PUCCH modulation order. As a result, unnecessary processing at the base station and insertion of dummy bit at the UE side are required.
A solution is sought.